Actually, it *is* possible to besiege a castle, but it is not easy.
First of all, you somehow manage to get another castle in the same
region (I told you it wasn't easy). Then you kill off all the garrisions
of the other castle. Lastly, you station an enormous *garrison* force
on the site of the other castle. The garrision eats up all the income
of the province, leaving none to be collected by the besiged castle.
Then you starve them out.
All in all, its easier/quicker/cheaper to just storm the castle (at
least, under the current combat system). The extra defensive value
of the castle is not enough to overcome superior numbers; if you get
a force of crossbowmen about twice as large as the number of castle
defenders, (e.g. if the castle has 100 defenders, attack with 200
crossbowmen) you'll probably win (unless the 100 defenders are all
elite guards or something). If you can;t come up with a force
this size, then odds are that you couldn't have done the seige
either.
-- Bron Campbell Nelson bron@sgi.com or possibly uunet!sgi.com!bron These statements are my own, not those of Silicon Graphics.